The Progressive Party's left-wing grew increasingly critical of the Isabelline Monarchy's political regime, feeling the parliamentary system to be stacked against them.
These examples pushed the Progressives' left-wing to adopt more hardline political demands incompatible with the existing constitutional monarchy, such as republicanism.
Led by Francisco Pi y Margall and Cristino Martos, the Democrats called for an end to the conservative parliamentary monarchy of Queen Isabella, and the full application of the Constitution of 1812.
Members of the Democratic Party were involved in a number of attempted insurrections in the 1850s and 1860s, most notably with the Loja Uprising in 1861.
[1] Following the Glorious Revolution of 1868, which deposed Queen Isabella, the party disintegrated due to conflicts between its different factions.